and on the Drift of the Eastern Counties. 19% 
into beds that unquestionably underlie, and pass gradually into, 
the great deposit of sands and gravels which cover the whole of 
Suffolk and are extensively developed in Norfolk and Essex, and 
which themselves pass upwards, without the least break, to 
the more widely spread northern Clay drift. 
The geological conditions under which the peculiar formation 
of beach Crags was accumulated demands a special considera- 
tion, from the circumstance that it seems to afford a solution of 
the question of the relationship between the Red and the Fluvio- 
marine Crag. The latter, occurring at intervals from Norwich 
to Thorpe, near Aldbro’, ceases almost at the place where the 
Red Crag first appears. The absence of any superposition in 
the two formations has hitherto left their relative ages in doubt; 
and since fluvio-marine conditions obtain in the one, and purely 
marine conditions in the other, inferences that might otherwise 
be drawn from a comparison of their fauna are consequently of 
less value. 
The unvarying N.N.E. to 8.S.W. direction presented every- 
where south of Hollesley, and from Melton and Bealings on the 
west to Bawdsey Cliff on the east, is precisely that possessed by 
the trend of the Coralline Crag, uncovered by any Red beach 
Crag, from the point where it first comes to the surface north 
of Aldbro’ to its termination at Gedgrave. This also is the 
direction which was detected by Sir Charles Lyell im the cliff of 
Coralline Crag buried in Red Crag at Sutton. According 
to the view I take, it is, in reconstructing the bay of the Red 
Crag, only necessary to assume the prolongation of that ridge 
or barrier of Coralline Crag in the same direction from Gedgrave 
southwards, over what is now covered by the sea. (See the con- 
tinuation-line suggested on the map.) The production of this 
ridge, composed as it is of the Bryozoon-bank of hard rock, 
capable of resisting the waves, would give rise to a long tongue- 
shaped bay running up between it and the shore-margin of soft 
London Clay, in which these successive accumulations and de- 
structions of beach-deposit might readily take place during 
slight intervals of subsidence. The direction of beaching up, 
then, would be determined by the particular contour of the bay 
and the direction from which the sea had access to it. The evi- 
dence available to show that the beach Crags never covered the 
greater part of what now remains of this barrier, although ne- 
cessarily only negative, is of the strongest character that such 
evidence can afford. Firstly, it is along this line, and there only, 
that the Coralline Crag occurs uncovered by the Red; secondly, 
the Coralline Crag consists of three parts,—the lower of sandy 
beds, rich in Mollusca, preserved nearly as they lived; the middle 
of the rocky Bryozoon-bank; and the upper of a thin bed, some 
